Sen. John McCain called yesterday for an end to the federal ban on offshore oil drilling, offering an aggressive response to high gasoline prices and immediately drawing the ire of environmental groups that the presumptive Republican presidential nominee has courted for months.

The move is aimed at easing voter anger over rising energy prices by freeing states to open vast stretches of the country's coastline to oil exploration. In a new Washington Post-ABC News poll, nearly 80 percent said soaring prices at the pump are causing them financial hardship, the highest in surveys this decade.

"We must embark on a national mission to eliminate our dependence on foreign oil," McCain told reporters yesterday. In a speech today, he plans to add that "we have untapped oil reserves of at least 21 billion barrels in the United States. But a broad federal moratorium stands in the way of energy exploration and production. . . . It is time for the federal government to lift these restrictions."

McCain's announcement is a reversal of the position he took in his 2000 presidential campaign and a break with environmental activists, even as he attempts to win the support of independents and moderate Democrats. Since becoming the presumptive GOP nominee in March, McCain has presented himself as a friend of the environment by touting his plans to combat global warming and his opposition to drilling in the Arctic National Wildlife Refuge and in the Everglades.

Representatives of several environmental groups criticized him for backing an idea they said would endanger the nation's most environmentally sensitive waters.

"It's disappointing that Senator McCain is clinging to the failed energy policies of the past," said Tiernan Sittenfeld, legislative director for the League of Conservation Voters.

Sierra Club political director Cathy Duvall said McCain "is using the environment as a way to portray himself as being different from George Bush. But the reality is that he isn't." The group began running radio commercials yesterday that criticize McCain's environmental record in the battleground state of Ohio.

Democratic Sen. Barack Obama joined the criticism, calling the idea of lifting the ban the wrong answer to out-of-control energy prices. "John McCain's plan to simply drill our way out of our energy crisis is the same misguided approach backed by President Bush that has failed our families for too long and only serves to benefit the big oil companies," Obama spokesman Hari Sevugan said.

Energy policy -- led by the spike in gas prices -- is now a top-tier issue in the campaign, forcing both candidates to shift their attention from other domestic issues and foreign affairs. Spot prices for a barrel of crude oil briefly hit an all-time high yesterday, flirting with $140 a barrel before settling back to a bit less than $134.

In the Post-ABC poll, conducted Thursday through Sunday, about half of those surveyed called high gas prices a serious burden, while the issue emerged for the first time during the campaign as a top concern for voters. Obama held double-digit leads over McCain as the candidate more trusted to deal with gasoline prices and energy policy.

While both candidates have spoken about the need to shift to cleaner energy sources, they have proposed different ways to do so.

McCain backs federal subsidies for building more nuclear power plants, which he considers the best way to reduce U.S. carbon dioxide emissions. He plans to begin outlining his energy proposals in the first of three major speeches today in Houston. Aides said the centerpiece of the speech will be the proposal to lift the ban on drilling, but McCain will also have harsh words for market speculators who are driving up the cost of oil.